View Compilation Error

0_0_25675033_12232.cpp: In function 'int main()':
0_0_25675033_12232.cpp:19:41: error: 'MOD' was not declared in this scope
    if(!(i&now))f[i^now]=(f[i^now]+f[i])%MOD;
                                         ^
0_0_25675033_12232.cpp:21:65: error: 'MOD' was not declared in this scope
         for(i=0;i<maxx;i++)if(!(i&now))f[i^now]=(f[i^now]-f[i])%MOD;
                                                                 ^
0_0_25675033_12232.cpp:24:55: error: 'MOD' was not declared in this scope
       for(i=1;i<maxx;i++)ans[id[i]]=(f[i]+ans[id[i]])%MOD;
                                                       ^